NEW YORK  Mark Knopfler and Emmylou Harris aren't claiming they set any precedents for speed in recording their new duets album, All the Roadrunning.

"They made the earth in seven days," Harris allows. "And I guess this album took about two weeks total, maybe."

Roadrunning, released last Tuesday, has nonetheless been in the works a long time. Knopfler and Harris are no strangers to collaborative projects; the veteran musicians and longtime mutual admirers met, in fact, while appearing on a TV special with Chet Atkins. Both later contributed to a Hank Williams tribute album, and the collective list of rock, folk and country notables that they've worked with separately reads like a who's who of roots artists.

Their busy schedules and individual obligations meant that Knopfler and Harris had to wait a few years to unveil the completed Roadrunning, which features two songs by Knopfler and two by Harris, one of the latter co-written by Kimmie Rhodes. Harris' raw, pure soprano and Knopfler's gruff baritone, enhanced by his distinctly lyrical guitar playing, convey an unfussy intimacy.

"We used two microphones, fairly close to each other," the onetime Dire Straits frontman explains over morning tea with Harris. "Emmy calls it the third voice, what happens when two people sing together and it's right."

The album "actually started by accident," Knopfler adds. "I was making a record that had some duets, (2003's) Sailing to Philadelphia. I had something going with Van Morrison and something with James Taylor, and I also wanted Emmy to sing, on what she called a Johnny-and-June song. I call it a courting song."

"I like his term better," Harris says, smiling.

"I like yours better," Knopfler insists.

The tune, Red Staggerswing, wound up being on Roadrunning, alongside more pensive numbers such as Love and Happiness and If This Is Goodbye. Knopfler says the latter was inspired by the desperate cellphone calls made by 9/11 victims facing their death, as recounted days later by celebrated author Ian McEwan.

"I waited a long time after reading the piece (by McEwan), but it stayed in my mind," Knopfler says. "I kept returning to those calls, to the idea that if there is a simple response to barbarity, it's 'I love you.' "

Love, by Harris and Rhodes, was inspired by a similar sense of vulnerability. "Being a parent makes you the most vulnerable you'll ever be, for the rest of your life," Harris says. "There's always a desperate need to protect our children. My mother is 85, and I live with her, and she makes me wear a bike helmet whenever she sees me toodling off out of the driveway."

Harris and Knopfler will soon be toodling off on tour, starting June 19 in Toronto and playing dates in Washington, New York, Boston, Chicago, Los Angeles and other cities before the month is out. Their road trip will no doubt be buoyed by fond memories of that short run in the studio.

"Each day with Mark was a different surprise," Harris says. "He didn't send me the material ahead of time; he would sit with an acoustic guitar and play it for me and for these fantastic musicians we had with us, inspiring us. It was an incredibly joyful experience."